Does the publisher alone decide on whether a license will be sold for use of a song and to whom or does he consult with the writer? In other words, as the songwriter, do I have any say whatsoever in how my song is used if I don't retain publishing rights?

If you give all of your rights to the publisher, they will place the song wherever they think it'll make them the most money. ... with or without your consent. If you split the rights with the publishing company, that would be another story. They're all in it for the money. So, developing a good relationship with your publishing company may get your input a better chance at being heard.